/* ============================================================
   BTC Mixers Lab — styles
   Palette: deep near-black bg, electric mint + amber accents
   ============================================================ */

:root {
  --bg: #0b0f14;
  --bg-alt: #0f151d;
  --surface: #131b25;
  --surface-2: #182231;
  --border: #1f2b3a;
  --border-strong: #2b3a4d;

  --text: #e6edf3;
  --text-dim: #a4b0c0;
  --text-muted: #6d7a8c;

  --accent: #52ffb8;
  --accent-2: #2fb3ff;
  --amber: #ffb547;
  --danger: #ff6b6b;

  --grad-accent: linear-gradient(135deg, #52ffb8 0%, #2fb3ff 100%);

  --font-display: 'Space Grotesk', system-ui, sans-serif;
  --font-body: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;

  --radius: 14px;
  --radius-lg: 20px;
  --shadow: 0 20px 60px -20px rgba(0,0,0,0.6);
  --container: 1200px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
  position: relative;
}

/* Lab grid background */
.lab-grid {
  position: fixed;
  inset: 0;
  z-index: -1;
  background-image:
    linear-gradient(rgba(82,255,184,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(82,255,184,0.03) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse at 50% 20%, #000 30%, transparent 80%);
  -webkit-mask-image: radial-gradient(ellipse at 50% 20%, #000 30%, transparent 80%);
  pointer-events: none;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* Typography */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin: 0 0 0.6em;
  color: var(--text);
}

h1 { font-size: clamp(2.2rem, 5vw, 3.6rem); }
h2 { font-size: clamp(1.7rem, 3vw, 2.4rem); }
h3 { font-size: 1.2rem; }
h4 { font-size: 1rem; letter-spacing: 0.02em; text-transform: uppercase; color: var(--text-dim); }

p { margin: 0 0 1em; color: var(--text-dim); }

a { color: var(--accent); text-decoration: none; transition: opacity 0.2s; }
a:hover { opacity: 0.75; }

.grad {
  background: var(--grad-accent);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ============ Header ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(11, 15, 20, 0.75);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
}
.logo-mark { width: 36px; height: 36px; }
.logo-text {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
}
.logo-text em {
  font-style: normal;
  color: var(--accent);
  font-weight: 500;
}

.site-nav {
  display: flex;
  gap: 32px;
}
.site-nav a {
  color: var(--text-dim);
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
}
.site-nav a:hover { color: var(--text); opacity: 1; }
.site-nav a::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -6px;
  height: 1px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s;
}
.site-nav a:hover::after { transform: scaleX(1); }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  width: 40px; height: 40px;
  cursor: pointer;
  padding: 10px 8px;
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--text);
  margin: 3px 0;
  transition: transform 0.25s, opacity 0.25s;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-5px) rotate(-45deg); }

/* ============ Hero ============ */
.hero {
  padding: 80px 0 100px;
  position: relative;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 60px;
  align-items: center;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-dim);
  border: 1px solid var(--border-strong);
  padding: 6px 12px;
  border-radius: 100px;
  margin-bottom: 24px;
}
.eyebrow .dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 12px var(--accent);
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.lede {
  font-size: 1.12rem;
  color: var(--text-dim);
  max-width: 560px;
  margin-bottom: 32px;
}

.hero-cta {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 48px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 24px;
  border-radius: 10px;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 0.98rem;
  transition: transform 0.15s, box-shadow 0.2s;
  cursor: pointer;
  border: none;
}
.btn-primary {
  background: var(--grad-accent);
  color: #0b0f14;
  box-shadow: 0 10px 30px -10px rgba(82,255,184,0.5);
}
.btn-primary:hover { transform: translateY(-2px); opacity: 1; }
.btn-ghost {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border-strong);
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); opacity: 1; }

.hero-stats {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  gap: 40px;
  border-top: 1px solid var(--border);
  padding-top: 28px;
}
.hero-stats li { display: flex; flex-direction: column; }
.hero-stats strong {
  font-family: var(--font-display);
  font-size: 2rem;
  color: var(--accent);
  font-weight: 600;
  line-height: 1;
}
.hero-stats span {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-top: 6px;
  max-width: 130px;
}

.hero-art {
  position: relative;
}
.hero-art svg {
  width: 100%;
  height: auto;
  max-width: 400px;
  margin: 0 auto;
  display: block;
  filter: drop-shadow(0 20px 60px rgba(82,255,184,0.15));
}

/* ============ Sections ============ */
.section { padding: 88px 0; position: relative; }
.section-alt { background: var(--bg-alt); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }

.section-head {
  max-width: 780px;
  margin-bottom: 48px;
}
.section-num {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent);
  letter-spacing: 0.08em;
  display: block;
  margin-bottom: 12px;
}
.section-sub {
  font-size: 1.05rem;
  color: var(--text-dim);
  margin-top: 12px;
}

/* Two-column intro block */
.two-col {
  display: grid;
  grid-template-columns: 1.4fr 1fr;
  gap: 40px;
  align-items: start;
}

.fact-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 28px;
}
.fact-card h3 { color: var(--accent); font-size: 1rem; margin-bottom: 10px; }
.fact-card p { margin: 0; }

/* ============ Architectures ============ */
.arch-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.arch-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: transform 0.25s, border-color 0.25s;
}
.arch-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
}
.arch-icon {
  width: 56px; height: 56px;
  border-radius: 12px;
  background: var(--surface-2);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}
.arch-icon svg { width: 100%; height: 100%; }

.pros-cons {
  list-style: none;
  padding: 0;
  margin: 18px 0 0;
  border-top: 1px solid var(--border);
  padding-top: 16px;
}
.pros-cons li {
  font-size: 0.9rem;
  padding: 4px 0 4px 20px;
  position: relative;
  color: var(--text-dim);
}
.pros-cons li.pro::before {
  content: "+";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: bold;
}
.pros-cons li.con::before {
  content: "−";
  position: absolute;
  left: 0;
  color: var(--amber);
  font-weight: bold;
}

/* ============ Mixer profile cards ============ */
.mixers-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.mixer-card {
  display: flex;
  gap: 20px;
  padding: 24px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  transition: transform 0.25s, border-color 0.25s;
  align-items: flex-start;
}
.mixer-card:hover {
  transform: translateY(-3px);
  border-color: var(--border-strong);
}
.mixer-logo {
  width: 72px;
  height: 72px;
  flex-shrink: 0;
  border-radius: 14px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  padding: 6px;
}
.mixer-logo img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  display: block;
}
.mixer-body {
  flex: 1;
  min-width: 0;
}
.mixer-head {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 8px;
}
.mixer-head h3 {
  margin: 0;
  font-size: 1.2rem;
  color: var(--text);
}
.mixer-tag {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--accent);
  padding: 3px 8px;
  border: 1px solid var(--accent);
  border-radius: 4px;
  opacity: 0.9;
}
.mixer-body p {
  margin: 0 0 14px;
  font-size: 0.95rem;
  line-height: 1.55;
}
.mixer-meta {
  list-style: none;
  padding: 12px 0 0;
  margin: 0;
  border-top: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
}
.mixer-meta li {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  position: relative;
  padding-right: 16px;
}
.mixer-meta li::after {
  content: "·";
  position: absolute;
  right: 4px;
  color: var(--border-strong);
}
.mixer-meta li:last-child { padding-right: 0; }
.mixer-meta li:last-child::after { content: none; }

.tiny-note {
  margin-top: 24px;
  font-size: 0.82rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

/* ============ Photo placeholders ============ */
.section-photo { padding: 20px 0; }
.photo-placeholder {
  height: 340px;
  border: 1.5px dashed var(--border-strong);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  background: repeating-linear-gradient(
    45deg,
    var(--bg-alt),
    var(--bg-alt) 10px,
    var(--bg) 10px,
    var(--bg) 20px
  );
}
.section-photo img {
  width: 100%;
  height: auto;
  border-radius: var(--radius-lg);
  display: block;
}

/* ============ Who uses ============ */
.who-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}
.who-grid article {
  padding: 28px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.who-grid h3 {
  color: var(--accent);
  font-size: 1.1rem;
}

/* ============ Steps ============ */
.steps {
  list-style: none;
  padding: 0;
  margin: 0;
  display: grid;
  gap: 16px;
  counter-reset: step;
}
.steps li {
  display: grid;
  grid-template-columns: 60px 1fr;
  gap: 24px;
  padding: 28px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  align-items: start;
  transition: border-color 0.2s;
}
.steps li:hover { border-color: var(--accent); }
.step-num {
  width: 44px; height: 44px;
  border-radius: 12px;
  background: var(--surface-2);
  border: 1px solid var(--border-strong);
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  justify-content: center;
}
.steps h3 { font-size: 1.1rem; margin-bottom: 6px; }
.steps p { margin: 0; }

/* ============ Signals ============ */
.signals-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}
.signal {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  position: relative;
  overflow: hidden;
}
.signal::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 3px; height: 100%;
  background: var(--grad-accent);
  opacity: 0.6;
}
.signal h3 { font-size: 1rem; margin-bottom: 8px; color: var(--text); }
.signal p { margin: 0; font-size: 0.95rem; }

/* ============ Expert block ============ */
.expert-block {
  max-width: 820px;
  margin: 0 auto;
  padding: 48px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  position: relative;
}
.expert-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  color: var(--amber);
  text-transform: uppercase;
  margin-bottom: 16px;
  padding: 4px 10px;
  border: 1px solid var(--amber);
  border-radius: 4px;
}
.expert-block blockquote {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.15rem;
  line-height: 1.6;
  color: var(--text);
}
.expert-block blockquote p:first-child::before {
  content: "\201C";
  font-size: 3.5rem;
  line-height: 0.8;
  color: var(--accent);
  display: block;
  margin-bottom: 8px;
  font-family: serif;
}
.expert-block footer {
  margin-top: 20px;
  font-family: var(--font-body);
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* ============ FAQ ============ */
.faq-list { max-width: 860px; }
.faq-list details {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 12px;
  transition: border-color 0.2s;
}
.faq-list details[open] { border-color: var(--accent); }
.faq-list summary {
  padding: 20px 24px;
  cursor: pointer;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 1.02rem;
  color: var(--text);
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after {
  content: "+";
  color: var(--accent);
  font-size: 1.4rem;
  font-family: var(--font-mono);
  transition: transform 0.25s;
}
.faq-list details[open] summary::after { transform: rotate(45deg); }
.faq-list details p {
  padding: 0 24px 22px;
  margin: 0;
  color: var(--text-dim);
}

/* ============ Footer ============ */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 64px 0 32px;
  background: var(--bg-alt);
  margin-top: 40px;
}
.footer-inner {
  display: grid;
  grid-template-columns: 1.3fr 2fr;
  gap: 60px;
}
.footer-brand p {
  margin-top: 16px;
  max-width: 340px;
  font-size: 0.92rem;
}
.footer-cols {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}
.footer-cols h4 { margin-bottom: 14px; }
.footer-cols a {
  display: block;
  color: var(--text-dim);
  font-size: 0.92rem;
  padding: 4px 0;
}
.footer-cols a:hover { color: var(--accent); opacity: 1; }
.footer-bottom {
  grid-column: 1 / -1;
  margin-top: 40px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

/* ============ Responsive ============ */
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; gap: 40px; }
  .hero-art { order: -1; max-width: 320px; margin: 0 auto; }
  .two-col { grid-template-columns: 1fr; gap: 24px; }
  .arch-grid { grid-template-columns: 1fr; }
  .who-grid { grid-template-columns: 1fr; }
  .signals-grid { grid-template-columns: 1fr; }
  .mixers-grid { grid-template-columns: 1fr; }
  .footer-inner { grid-template-columns: 1fr; gap: 40px; }
  .footer-cols { grid-template-columns: repeat(3, 1fr); }
}

@media (max-width: 720px) {
  .site-nav { display: none; }
  .site-nav.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 72px; left: 0; right: 0;
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
    padding: 24px;
    gap: 20px;
  }
  .nav-toggle { display: block; }
  .section { padding: 64px 0; }
  .hero { padding: 48px 0 64px; }
  .hero-stats { gap: 24px; flex-wrap: wrap; }
  .hero-stats strong { font-size: 1.5rem; }
  .expert-block { padding: 32px 24px; }
  .steps li { grid-template-columns: 44px 1fr; gap: 16px; padding: 20px; }
  .footer-cols { grid-template-columns: 1fr; gap: 24px; }
  .photo-placeholder { height: 220px; }
  .mixer-card { padding: 20px; gap: 16px; }
  .mixer-logo { width: 56px; height: 56px; }
}